InSight's objectives are to place a seismometer, called SEIS, on the surface of Mars to measure seismic activity and provide accurate 3D models of the planet's interior; and measure internal heat flow using a heat probe called HP3 to study Mars' early geological evolution.[18] This could bring a new understanding of how the Solar System's terrestrial planets – Mercury, Venus, Earth, Mars – and Earth's Moon form and evolve.

The lander was originally planned for launch in March 2016.[12][19] Following a persistent vacuum failure in the SEIS instrument prior to launch, with the 2016 launch window missed, InSight was returned to Lockheed Martin's facility in Denver, Colorado, for storage. NASA officials decided in March 2016 to delay launching InSight to May 2018.[6] This allowed time for the seismometer issue to be fixed, although it increased the cost from the previous US$675 million to a total of US$830 million.[20] By reusing technology from the Mars Phoenix lander, which successfully landed on Mars in 2008, mission costs and risks were reduced.[21]

History

Discovery Program selection

InSight comes together with the backshell and surface lander being joined, 2015.

InSight was initially known as GEMS (Geophysical Monitoring Station), but its name was changed in early 2012 following a request by NASA.[22] Out of 28 proposals from 2010,[23] it was one of the three Discovery Program finalists receiving US$3 million in May 2011 to develop a detailed concept study.[24] In August 2012, InSight was selected for development and launch.[12] Managed by NASA's Jet Propulsion Laboratory (JPL) with participation from scientists from several countries, the mission was cost-capped at US$425 million, not including launch vehicle funding.[25]

Schedule issues

Lockheed Martin began construction of the lander on 19 May 2014,[26] with general testing starting in 27 May 2015.[27]

A persistent vacuum leak in the CNES-supplied seismometer known as the Seismic Experiment for Interior Structure (SEIS) led NASA to postpone the planned launch in March 2016 to May 2018. When InSight was delayed, the rest of the spacecraft was returned to Lockheed Martin's factory in Colorado for storage, and the Atlas V rocket intended to launch the spacecraft was reassigned to the WorldView-4 mission.[28]

On 9 March 2016, NASA officials announced that InSight would be delayed until the 2018 launch window at an estimated cost of US$150 million.[6][29] The spacecraft was rescheduled to launch on 5 May 2018 for a Mars landing on 26 November at 3 p.m. The flight plan remained unchanged with launch using an Atlas V rocket from Vandenberg Air Force Base in California.[6][29] NASA's Jet Propulsion Laboratory was tasked with redesigning and building a new vacuum enclosure for the SEIS instrument, while CNES conducted instrument integration and testing.[30][31]

On 22 November 2017 InSight completed testing in a thermal vacuum, also known as TVAC testing, where the spacecraft is put in simulated space conditions with reduced pressure and various thermal loads.[32] On 23 January 2018, after a long storage, its solar panels were once again deployed and tested, and a second silicon chip containing 1.6 million names from the public was added to the lander.[33]

Science background

The Apollo 11 seismometer, 1969

Vibrations

Seismometers on both Viking spacecraft were mounted on the lander, and picked up vibrations from various operations of the lander and from the wind.[34] However, the Viking 1 lander's seismometer did not deploy properly in 1976 after it landed; the seismometer remained locked and did not unlock. The Viking 2 seismometer did unlock, and was able to vibrate and return data to Earth.[35][36] One problem was accounting for other data, as this was the issue with an event detected on Sol 80 by the Viking 2 seismometer.[37] When this event was recorded, no wind data were recorded at the same time, so it was not possible to determine if the data indicated a seismic event or wind gust. However, for the Sol 80 event the main problem was not wind noise per se, but rather a lack of other data to rule out other sources of vibrations.[38] Two other problems were the location of the lander and that a certain level of wind on Mars caused a loss of sensitivity for the Viking 2 seismometer.[39] InSight has many other sensors, is placed directly on the surface, and also has a wind shield.

Despite the difficulties, the Viking 2 seismometer readings were used to estimate a Martian geological crust thickness between 14 and 18 km (8.7 and 11.2 mi) at the Viking 2 lander site.[40] The Viking 2 seismometer did detect vibrations from Mars winds complementing the meteorology results.[40][41] There was the aforementioned candidate for a possible marsquake, but is not particularly definitive. The wind data did prove useful in its own right, and despite the limitations of the data, widespread and large marsquakes were not detected.[42]

One of the aspects of the InSight mission is to compare the Earth, Moon, and Mars seismic data to learn more.[46]

Well, seismic investigation is really the heart of this mission. Seismology is the method that we've used to gain almost everything we know, all the basic information about the interior of the Earth, and we also used it back during the Apollo era to understand and to measure sort of the properties of the inside of the moon. And so, we want to apply the same techniques but use the waves that are generated by Mars quakes, by meteorite impacts to probe deep into the interior of Mars all the way down to its core.

Nutation

Radio Doppler measurements were taken with Viking and twenty years later with Mars Pathfinder, and in each case the axis of rotation of Mars was estimated. By combining this data the core size was constrained, because the change in axis of rotation over 20 years allowed a precession rate and from that the planet's moment of inertia to be estimated.[48]InSight's measurements of crust thickness, mantle viscosity, core radius and density, and seismic activity should result in a three- to tenfold increase in accuracy compared to current data.[49]

Objectives

The InSight mission placed a single stationary lander on Mars to study its deep interior and address a fundamental issue of planetary and Solar System science: understanding the processes that shaped the rocky planets of the inner Solar System (including Earth) more than four billion years ago.[50]

Comparison of the interiors of Earth, Mars and the Moon (artist concept)

InSight's primary objective is to study the earliest evolutionary history of the processes that shaped Mars. By studying the size, thickness, density and overall structure of Mars' core, mantle and crust, as well as the rate at which heat escapes from the planet's interior, InSight will provide a glimpse into the evolutionary processes of all of the rocky planets in the inner Solar System.[51][50] The rocky inner planets share a common ancestry that begins with a process called accretion. As the body increases in size, its interior heats up and evolves to become a terrestrial planet, containing a core, mantle and crust.[52] Despite this common ancestry, each of the terrestrial planets is later shaped and molded through a poorly understood process called differentiation. InSight mission's goal is to improve the understanding of this process and, by extension, terrestrial evolution, by measuring the planetary building blocks shaped by this differentiation: a terrestrial planet's core, mantle and crust.[52]

InSight lander on Mars (artist concept)

The mission will determine if there is any seismic activity, measure the rate of heat flow from the interior, estimate the size of Mars' core and whether the core is liquid or solid.[53] This data would be the first of its kind for Mars.[49] It is also expected that frequent meteor airbursts (10–200 detectable events per year for InSight) will provide additional seismo-acoustic signals to probe the interior of Mars.[54] The mission's secondary objective is to conduct an in-depth study of geophysics, tectonic activity and the effect of meteorite impacts on Mars, which could provide knowledge about such processes on Earth. Measurements of crust thickness, mantle viscosity, core radius and density, and seismic activity should result in a three- to tenfold increase in accuracy compared to current data.[49] This is the first time a robotic lander dug this deep into the martian crust.

In terms of fundamental processes shaping planetary formation, it is thought that Mars contains the most in-depth and accurate historical record, because it is big enough to have undergone the earliest accretion and internal heating processes that shaped the terrestrial planets, but is small enough to have retained signs of those processes.[50] The science phase is expected to last for two years.[1]

Design

The InSight lander with solar panels deployed in a cleanroom

The mission further develops a design based on the 2008 Phoenix Mars lander.[55] Because InSight is powered by solar panels, it landed near the equator to enable maximum power for a projected lifetime of two years (1 Martian year).[1] The mission includes two relay microsatellites called Mars Cube One (MarCO) that launched with InSight but were flying in formation with InSight to Mars.[56]

Three major aspects to the InSight spacecraft are the cruise stage, the entry, descent, and landing system, and the lander.[57]

Payload

InSight's lander payload has a total mass of 50 kg, including science instruments and support systems such as the Auxiliary Payload Sensor Suite, cameras, the instrument deployment system, and a laser retroreflector.[3]

InSight will perform three major experiments using SEIS, HP3 and RISE.[65] SEIS is a very sensitive seismometer, measuring vibrations; HP3 involves a burrowing probe to measure the thermal properties of the subsurface.[66] RISE uses the radio communication equipment on the lander and on Earth to measure the overall movement of planet Mars that could reveal the size and density of its core.[67]

The Heat Flow and Physical Properties Package (HP3), provided by the German Aerospace Center (DLR), is a self-penetrating heat flow probe.[71][55][73][74] Referred to as a "self-hammering nail" and nicknamed "the mole", it was designed to burrow as deep as 5 m (16 ft) below the Martian surface while trailing a tether with embedded heat sensors to measure how efficiently heat flows through Mars' core, and thus reveal unique information about the planet's interior and how it has evolved over time.[71][55][73][74] It trails a tether containing precise temperature sensors every 10 cm (3.9 in) to measure the temperature profile of the subsurface.[71][75] The tractor mole of the instrument was provided by the Polish company Astronika.[76]

The Rotation and Interior Structure Experiment (RISE) led by the Jet Propulsion Laboratory (JPL), is a radio science experiment that will use the lander's X band radio to provide precise measurements of planetary rotation to better understand the interior of Mars.[77] X band radio tracking, capable of an accuracy under 2 cm, will build on previous Viking program and Mars Pathfinder data.[71] The previous data allowed the core size to be estimated, but with more data from InSight, the nutation amplitude can be determined.[71] Once spin axis direction, precession, and nutation amplitudes are better understood, it should be possible to calculate the size and density of the Martian core and mantle.[71] This should increase the understanding of the formation of terrestrial planets (e.g. Earth) and rocky exoplanets.[71]

Laser RetroReflector for InSight (LaRRI) is a corner cuberetroreflector provided by the Italian Space Agency and mounted on InSight's top deck.[78][79] It will enable passive laser range-finding by orbiters even after the lander is retired,[80] and would function as a node in a proposed Mars geophysical network.[81] This device previously flew on the Schiaparelli lander as the Instrument for Landing-Roving Laser Retroreflector Investigations (INRRI), and is an aluminum dome 54 mm (2.1 in) in diameter and 25 g (0.9 oz) in mass featuring eight fused silica reflectors.[80]

Instrument Deployment Arm (IDA) is a 2.4 m robotic arm that will be used to deploy the SEIS and HP3 instruments to Mars' surface.[48] It also features the IDC camera.

The Instrument Deployment Camera (IDC) is a color camera based on the Mars Exploration Rover and Mars Science Laboratorynavcam design. It is mounted on the Instrument Deployment Arm and will image the instruments on the lander's deck and provide stereoscopic views of the terrain surrounding the landing site. It features a 45-degree field of view and uses a 1024 × 1024 pixel CCD detector.[82] The IDC sensor was originally black and white for best resolution; a program was enacted that tested with a standard hazcam and, since development deadlines and budgets were met, it was replaced with a color sensor.[83]

The Instrument Context Camera (ICC) is a color camera based on the MER/MSL hazcam design. It is mounted below the lander's deck, and with its wide-angle 120-degree panoramic field of view will provide a complementary view of the instrument deployment area. Like the IDC, it uses a 1024 × 1024 pixel CCD detector.[82]

Test of the 2.4 meter long Instrument Deployment Arm, seen deploying SEIS

The two relay 6U cubesats were part of the overall InSight program, and were launched at the same time as the lander but they were attached to the centaur upper stage (InSight's second stage in the launch).[84] They were ejected from the stage after launch and coasted to Mars independent of the main InSight cruise stage with the lander.[85]

Journey to Mars

Launch

On 28 February 2018, InSight was shipped via C-17 cargo aircraft from the Lockheed Martin Space Systems building in Denver to the Vandenberg Air Force Base in California in order to be integrated to the launch vehicle.[86] The lander was launched on 5 May 2018 and arrived on Mars at approximately 19:54 UTC on 26 November 2018.

The journey to Mars took 6.5 months across 484 million km (301 million mi) for a touchdown on 26 November.[5][16] After a successful landing, a three-month-long deployment phase commenced as part of its two-year (a little more than one Martian year) prime mission.[91][92]

Service Tower Rolls Back

Pre-Launch

InSight heading to space

Cruise

Animation of InSight's trajectory from 5 May 2018 to 26 November 2018InSight·Earth·Mars

After its launch from Earth on the 5th of May in 2018, it coasted through interplanetary space for 6.5 months traveling across 484 million km (301 million mi) for a touchdown on the 26th November in that year.[5][16]

InSight cruise stage departed Earth at a speed of 6,200 miles per hour (10,000 kilometers per hour).[93] The MarCo probes were ejected from the 2nd stage Centaur booster and traveled to Mars independent of the InSight cruise stage, but they were all launched together

During the cruise to Mars, the InSight cruise stage makes several course adjustments, and the first of these (TCM-1) took place on May 22, 2018.[94] The cruise stage that carries the lander includes solar panels, antenna, star trackers, sun sensor, inertial measurement unit among its technologies.[95] The thrusters are actually on the InSight lander itself, but there are cutouts in the shell so the relevant rockets can vent into space.[96]

The final course correction was November 25, 2018, the day before its touch down.[97] A few hours before making contact with the Martian atmosphere, the cruise stage was jettisoned, on 26 November 2018.[98]

InSight on way to Mars

Exterior (artist concept)

Interior

Entry, Descent, and Landing

First light on the surface of Mars from the Instrument Context Camera (ICC, left) and the Instrument Deployment Camera (IDC, right) November 26, 2018 (Touch down-day // Sol 0)

On 26 November 2018, at approximately 19:53 UTC, mission controllers received a signal via the Mars Cube One (MarCO) satellites that the spacecraft had successfully touched down[13] at Elysium Planitia.[5][14][16] After landing, the mission will take three months to deploy and commission the geophysical science instruments.[91][92] It will then begin its mission of observing Mars, which is planned to last for two years.[1]

The mass that entered the atmosphere of Mars was 1,340 pounds (608 kilograms) .[99]

A simulated view of NASA's InSight lander about to land on the surface of Mars.

On 26 November 2018 InSight successfully touched down in Elysium Plantia.[13]

A few hours after landing, NASA's 2001 Mars Odyssey orbiter relayed signals indicating that InSight'ssolar panels had successfully unfurled and are generating enough electrical power to recharge its batteries daily. Odyssey also relayed a pair of images showing InSight's landing site.[104] More images would be taken in stereo pairs to create 3D images, allowing InSight to find the best locations on the surface to place the heat probe and seismometer. Over the next few weeks, InSight would check health indicators and monitor both weather and temperature conditions at the landing site.[91]

Landing site

As InSight's science goals are not related to any particular surface feature of Mars, potential landing sites were chosen on the basis of practicality. Candidate sites needed to be near the equator of Mars to provide sufficient sunlight for the solar panels year round, have a low elevation to allow for sufficient atmospheric braking during EDL, flat, relatively rock-free to reduce the probability of complications during landing, and soft enough terrain to allow the heat flow probe to penetrate well into the ground.

An optimal area that meets all these requirements is Elysium Planitia, so all 22 initial potential landing sites were located in this area.[105] The only two other areas on the equator and at low elevation, Isidis Planitia and Valles Marineris, are too rocky. In addition, Valles Marineris has too steep a gradient to allow safe landing.[8]
In September 2013, the initial 22 potential landing sites were narrowed down to 4, and the Mars Reconnaissance Orbiter was then used to gain more information on each of the 4 potential sites before a final decision was made.[8][106] Each site consists of a landing ellipse that measures about 130 by 27 km (81 by 17 mi).[107]

In March 2017, scientists from the Jet Propulsion Laboratory announced that the landing site had been selected. It is located in western Elysium Planitia at 4°30′N 135°54′E﻿ / ﻿4.5°N 135.9°E﻿ / 4.5; 135.9﻿ (InSight landing site).[108] The landing site is about 600 km (370 mi) north from where the Curiosity rover is operating in Gale Crater.[109]

On 26 November 2018 the spacecraft successfully touched down at its landing site,[13] and in early December 2018 InSight lander and EDL components were imaged from space on the surface of Mars.[110]

InSight landing zone is in the south and west of this grid, near 4.5 degree North and 136 degrees East, this is south and to the west of Elysium Mons and Eddie crater

Image footprints by HiRise on Mars Reconnaissance Orbiter for studying the planned Insight landing ellipse. From east to west the scale is about 160 km (100 mi)

InSight final landing location (red dot)(13 December 2018)

Artist's concept depicts NASA's InSight lander after it has deployed its instruments on the Martian
surface.

NASA’s InSight spacecraft unlatched its robotic arm on Nov. 27, 2018, the day after it landed on Mars.

Surface operations

On 26 November 2018, NASA reported that the InSight lander had landed successfully on Mars. The meteorological suite (TWINS) and magnetometer are operational, and the mission will take up to three months to deploy and commission the geophysical science instruments.[91][92] One of the first critical tasks was to unfurl the solar panels for the batteries to be recharged.[111] After landing, the dust was allowed to settle for a few hours, time during which the solar array array motors were warmed up and then the solar panels were unfurled.[112][113] The lander then reported its systems' status, acquired some images, and it powered down to sleep mode for its first night on Mars. On its first sol on Mars it set a new solar power record of 4.6 kilowatt-hours generated for a single Martian day (known as a "sol").[62] This amount is enough to support operations and deploy the sensors.[114]

InSight on the surface of Mars (6 December 2018)

Deck and science instruments

Robotic arm over Martian soil

Robotic arm and deck

One of its two solar panels

Set up of wind and thermal shield

Set up of heat probe (HP3)

InSight – seismometer deployed, first time onto the surface of another planet (19 December 2018)[115]

On December 7, 2018 InSight recorded the sounds of Martian winds with SEIS, which is able to record vibrations within human hearing range, although rather low (aka subwoofer-type sounds), and these were sent back to Earth.[116] This was the first time the sound of Mars wind was heard after two previous attempts.[117]

On 19 December 2018, the SEIS instrument was deployed onto the surface of Mars next to the lander by its robotic arm,[115] and it was commissioned on 4 February 2019.[118] After the seismometer became fully operational, the heat probe instrument was deployed on 12 February 2019,[119] and it should reach its maximum depth of 5 m (16 ft) about two months after the mole is activated.[120]

MarCO spacecraft

The Mars Cube One (MarCO) spacecraft are a pair of 6U CubeSats that piggybacked with the InSight mission to test CubeSat navigation and endurance in deep space, and to help relay real-time communications (eight minute delay)[92] during the probe's entry, descent and landing (EDL) phase.[121][122] The two 6U CubeSats, named MarCO A and B, are identical,[123] they were launched along with InSight, but separated soon after reaching space,[124] and they flew as a pair for redundancy while flanking the lander.[56] They did not enter orbit, but flew past Mars during the EDL phase of the mission and relayed InSight's telemetry in real time.[125][126] On 5 February 2019, NASA reported that the CubeSats went silent, and are unlikely to be heard from again.[127]

Team and participation

Insight team at JPL

The InSight science and engineering team includes scientists and engineers from many disciplines, countries and organizations. The science team assigned to InSight includes scientists from institutions in the U.S., France, Germany, Austria, Belgium, Canada, Japan, Switzerland, Spain, Poland and the United Kingdom.[131]

Mars Exploration Rover project scientist W. Bruce Banerdt is the principal investigator for the InSight mission and the lead scientist for the SEIS instrument.[132]Suzanne Smrekar, whose research focuses on the thermal evolution of planets and who has done extensive testing and development on instruments designed to measure the thermal properties and heat flow on other planets,[133] is the lead for InSight's HP3 instrument. The Principal Investigator for RISE is William Folkner at JPL.[134] The InSight mission team also includes project manager Tom Hoffman and deputy project manager Henry Stone.[131] Major contributing agencies and institutions are:[79]

NASA team cheers as the InSight Lander touches down on Mars. (26 November 2018)[13]

Name chips

As part of its public outreach, NASA organized a program where members of the public were able to have their names sent to Mars aboard InSight. Due to its launch delay, two rounds of sign-ups were conducted totaling 2.4 million names:[135][136] 826,923 names were registered in 2015[137] and a further 1.6 million names were added in 2017.[138] An electron beam was used to etch letters only ​1⁄1000 the width of a human hair onto 8 mm (0.3 in) silicon wafers.[137] The first chip was installed on the lander in November 2015 and the second on 23 January 2018.[137][138]

Name chips on InSight

One name chip installed

The first name chip for InSight

The second name chip, inscribed with 1.6 million names, is placed on InSight in January 2018.

^ abcdeThe Editorial Board (27 November 2018). "Mars Beckons - Scientists hope to uncover some of the secrets of that distant world — and maybe some of our own". The New York Times. Retrieved 28 November 2018.

^ abChang, Kenneth (26 November 2018). "NASA's Mars InSight Landing: Back to the Red Planet Once Again – The NASA spacecraft will arrive at the red planet today and attempt to reach its surface in one piece". The New York Times. Retrieved 26 November 2018.

Launches are separated by dashes ( – ), payloads by dots ( · ), multiple names for the same satellite by slashes ( / ). CubeSats are smaller.Manned flights are bolded. Launch failures are in italics. Payloads deployed from other spacecraft are (enclosed in brackets).